Metal-organic framework-derived Fe3C@NC nanohybrids as highly-efficient oxygen reduction electrocatalysts in both acidic and basic media

Abstract

Developing low-cost and high-performance non-precious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) is of critical importance for commercialization of fuel cells. Herein, we report a NPMC consisting of Fe3C nanoparticles encapsulated in mesoporous N-doped carbon (N-C), which is synthesized by a simple two-step strategy comprising pyrolysis of a mixture of MIL-100(Fe) and dicyandiamide under inert atmosphere, followed by treatment of the product with acidic solution to leach removable Fe3C species from the material. Fe3C@NC-800 (the material prepared at 800 °C) exhibits superior electrocatalytic activity, high durability and excellent methanol tolerance for ORR, with catalytic performance comparable to that of commercial Pt/C in both alkaline and acidic media. Fe3C@NC-800's excellent catalytic activity and stability in ORR are due to its large BET surface area, its large total pore volume, its nitrogen dopants and the cooperative effects between the reactive functionalities in it as well as its excellent conductivity.